Multi-phase brushless DC motor control integrated circuit having magnetic sensor and band-gap temperature sensor formed thereon

Abstract

An integrated circuit for implementing brushless DC motor control includes a substrate, a band gap temperature sensor, and a magnetic sensor. The substrate has a temperature output pin for connection to an external device and a magnetic sensor output pin for connection to the external device. The band gap temperature sensor is formed on the substrate and is configured to sense temperature and supply a temperature signal representative of the sensed temperature to the temperature output pin. The magnetic sensor is formed on the substrate and is configured to sense magnetic field variations and supply a sensor output signal representative thereof to the magnetic sensor output pin.

What is claimed is: 
     
       1. A brushless DC motor control system, comprising:
 an integrated circuit configured to at least selectively supply rotating armature position signals, the integrated circuit comprising:
 a substrate, 
 a magnetic sensor formed on the substrate and configured, when energized, to sense magnetic field variations and supply the rotating armature position signals in response thereto, and 
 a band gap temperature sensor formed on the substrate, the band gap temperature sensor configured to sense temperature and supply a temperature signal representative of the sensed temperature; and 
 
 a motor controller coupled to receive the rotating armature position signals and the temperature signal, the motor controller configured, in response to the rotating armature position signals, to selectively supply current, and further configured, in response to the temperature signal, to (i) de-energize the magnetic sensor when the temperature signal is representative of a temperature greater than a first predetermined temperature and (ii) energize the magnetic sensor when the temperature signal is representative of a temperature less than a second predetermined temperature, the second predetermined temperature less than the first predetermined temperature. 
 
     
     
       2. The brushless DC motor control system of  claim 1 , wherein the magnetic sensor is a Hall sensor. 
     
     
       3. The brushless DC motor control system of  claim 2 , wherein the Hall sensor is configured as a bipolar latching type of Hall sensor. 
     
     
       4. The brushless DC motor control system of  claim 1 , wherein the magnetic sensor comprises one or more anisotropic magnetic resistors (AMRs). 
     
     
       5. The brushless DC motor control system of  claim 1 , wherein the integrated circuit consists of four leads. 
     
     
       6. The brushless DC motor control system of  claim 1 , further comprising:
 a temperature compensation circuit formed on the substrate, the temperature compensation circuit coupled to receive the temperature signal and the sensor output signal and configured, in response thereto, to supply a temperature compensated sensor output signal. 
 
     
     
       7. The brushless DC motor control system of  claim 1 , wherein the motor controller comprises:
 a driver circuit coupled to receive phase switching signals and configured, in response to the switching signals, to selectively supply the current; and 
 commutation logic coupled to the driver circuit and further coupled to receive the rotating armature position signals, the commutation logic configured, in response to the rotating armature position signals, to supply the phase switching signals. 
 
     
     
       8. An integrated circuit, comprising:
 a substrate; 
 a band gap temperature sensor formed on the substrate, the band gap temperature sensor configured to sense temperature and supply a temperature signal representative of the sensed temperature; and 
 a magnetic sensor formed on the substrate, the magnetic sensor coupled to receive the temperature signal from the band gap temperature sensor and configured, in response thereto, to selectively switch between an ENABLE state, in which the magnetic sensor senses magnetic field variations and supplies a sensor output signal in response thereto, and a DISABLE state, in which the magnetic sensor does not supply the output signal, 
 wherein the magnetic sensor is configured to:
 switch from the ENABLE state to the DISABLE state when the temperature signal is representative of a temperature greater than a first predetermined temperature, and 
 switch from the DISABLE state to the ENABLE state when the temperature signal is representative of a temperature less than a second predetermined temperature, the second predetermined temperature less than the first predetermined temperature. 
 
 
     
     
       9. The integrated circuit of  claim 8 , wherein the magnetic sensor is a Hall sensor. 
     
     
       10. The integrated circuit of  claim 8 , wherein the magnetic sensor comprises one or more anisotropic magnetic resistors (AMRs).